1. Field of the Invention
This invention relates to an apparatus and method for penetrating a walled enclosure to dispense a fire fighting agent within the enclosure.
2. Description of the Prior Art
Physically entering an aircraft or similar enclosure to fight a fire or dispense a fire fighting agent in an explosive atmosphere can be very dangerous, exposing the fire fighter to an explosion or other catastrophe. The classical technique used to fight fires in a building structure involves breaking through windows with an axe or other tool, breaking down or chopping through a door or chopping through a wall or roof. This method has proven to be unsatisfactory in many instances. When windows are broken there is a danger of injury from glass cuts. When the fire inside the building is located close to the wall or door being penetrated, there is also a danger from hot gases and flames, or an explosive action when the building is penetrated. In addition, the use of axes or other penetrating tools is time-consuming and requires considerable effort, allowing the fire to continue burning and spread while the wall is being penetrated.
As a result of the above problems, various devices have been developed for more rapidly penetrating a walled enclosure and introducing a fire fighting agent into the interior. In U.S. Pat. No. 4,271,909 to Chatfield, Jr. et al., a modular fire fighting tool is disclosed in which a cylindrical barrel with a drill bit or other penetrating tool at its front end extends forward from a turbine. The turbine is driven by water or other fire extinguishing fluid, and rotates the drill bit to cut a hole in the building wall. The barrel is then inserted into the interior of the building, and a valve is operated which allows water to flow down the barrel and out through outlet openings located behind the bit to extinguish the fire. In U.S. Pat. No. 3,865,194 to Chatfield, Jr. another hydraulically operated fire extinguishing drill is disclosed. After a hole has been cut in the enclosure wall and the barrel inserted, a valve is operated to permit water to issue from the end of the tool and extinguish the flame. U.S. Pat. No. 2,251,175 to Tappe is somewhat similar in concept to the '909 patent above, in that it uses a hydraulically operated circular saw to cut a hole in a vessel, with a valve controlling the flow of water out of the barrel once the hole has been cut. The tool is mounted on an extension carried by a mobile support frame. Another penetrator/barrel arrangement is disclosed in U.S. Pat. No. 4,147,216 to Schnepfe, Jr. et al. In this device, which is particularly designed for aircraft fires, a cartridge is fired to drive the cutter through the aircraft skin. The barrel is then moved through the opening and a fire fighting agent is dispensed into the interior of the aircraft. Another device designed for fighting aircraft fires is disclosed in U.S. Pat. No. 2,857,005 to Medlock. In this patent a penetration tool is carried at the end of an extension arm mounted on a truck. The tool punches through the aircraft shell by the forward motion of the truck, which then backs away to leave an outlet in place through which a fire fighting agent can be sprayed into the interior of the aircraft.
The foregoing devices represent improvements in the fire fighting art, in that they permit a more rapid penetration of an aircraft or other enclosure to fight a fire inside. However, they do not solve all of the potential problems. A considerable amount of heat is generated when drilling through an aircraft skin or the like, and hot chips as wall as sparks can be discharged into the interior of the craft. This excessive heat can be very dangerous in the presence of an explosive atmosphere inside the craft. Furthermore, a considerable back pressure is developed when the tool is inserted into a craft and begins to dispense a fire fighting fluid. This pressure can make it difficult to control the tool, and may even force the tool back out of the craft. In addition, some of the prior devices are quite cumbersome and difficult to manually manipulate.